From 6736966974aea334e119cdb0b6c330066061bf91 Mon Sep 17 00:00:00 2001
From: quou <quou@disroot.org>
Date: Fri, 27 Dec 2024 11:35:01 +1100
Subject: basic text rendering

---
 Makefile             |  10 +-
 c2.cpp               |  21 +++-
 intermediate/ui.glsl |  56 +++++++++++
 todo.txt             |   2 +-
 ui.cpp               | 275 +++++++++++++++++++++++++++++++++++++++++++++++++++
 ui.hpp               |  60 +++++++++++
 6 files changed, 418 insertions(+), 6 deletions(-)
 create mode 100644 intermediate/ui.glsl
 create mode 100644 ui.cpp
 create mode 100644 ui.hpp

diff --git a/Makefile b/Makefile
index ac6149c..fbc4cf4 100644
--- a/Makefile
+++ b/Makefile
@@ -2,11 +2,11 @@
 
 target = c2
 data_dir = data
-shaders = $(data_dir)/triangle.csh
+shaders = $(data_dir)/triangle.csh $(data_dir)/ui.csh
 textures = $(data_dir)/22.tex $(data_dir)/kita.tex
 packed_files = $(shaders) $(textures)
 tools = qstd cfg sc
-objects = app.o c2.o video.o pipeline.o asset.o
+objects = app.o c2.o video.o pipeline.o asset.o ui.o
 includes = -Iqstd
 defines = -Dplat_x86 -Dplat_posix -Dplat_x11 -Dallocation_default_alignment=8
 cflags = -MMD -MF $(basename $@).d $(includes) $(defines) $(DEBUG_COMPILE_FLAG)
@@ -37,6 +37,9 @@ pack: $(packed_files) packer
 data/triangle.csh: intermediate/triangle.glsl | $(data_dir) sc
 	./sc/sc intermediate/triangle.glsl $(data_dir)/triangle.csh
 
+data/ui.csh: intermediate/ui.glsl | $(data_dir) sc
+	./sc/sc intermediate/ui.glsl $(data_dir)/ui.csh
+
 data/22.tex: intermediate/22.bmp | $(data_dir) convtexture
 	./convtexture intermediate/22.bmp $(data_dir)/22.tex bc1
 
@@ -55,6 +58,9 @@ pipeline.o:
 asset.o:
 	$(CXX) -c $(cflags) asset.cpp -o asset.o
 
+ui.o:
+	$(CXX) -c $(cflags) ui.cpp -o ui.o
+
 c2.o:
 	$(CXX) -c $(cflags) c2.cpp -o c2.o
 
diff --git a/c2.cpp b/c2.cpp
index 3ea05b9..223e0b0 100644
--- a/c2.cpp
+++ b/c2.cpp
@@ -1,4 +1,5 @@
 #include "app.hpp"
+#include "ui.hpp"
 #include "video.hpp"
 extern "C" {
 #include "plat.h"
@@ -9,6 +10,7 @@ extern "C" {
 
 #define video_arena_size (1024 * 1024 * 16)
 #define asset_arena_size (1024 * 1024 * 4)
+#define ui_arena_size    (1024 * 16)
 #define per_frame_memory_size (1024 * 1024)
 
 static float verts[] = {
@@ -64,15 +66,15 @@ struct Config_Buffer {
 };
 
 int main() {
-	Arena video_arena;
-	Arena asset_arena;
+	Arena video_arena, asset_arena, ui_arena;
 	Asset_Arena assets;
 	Device* dev;
-	Shader* shader;
+	Shader* shader, * ui_shader;
 	Texture* texture;
 	Texture* texture2;
 	Buffer_Id vbo, cbuf;
 	Sampler_Id clamped_linear;
+	UI* ui;
 	C2* app = App::create<C2>("c2");
 	void* per_frame;
 	int frame = 0;
@@ -87,10 +89,16 @@ int main() {
 		arena_alloc(app->arena, asset_arena_size),
 		asset_arena_size
 	);
+	init_arena(
+		&ui_arena,
+		arena_alloc(app->arena, ui_arena_size),
+		ui_arena_size
+	);
 	assets.init(&asset_arena, "pack");
 	dev = Device::create(&video_arena, app); 
 	app->dev = dev;
 	shader = (Shader*)assets.load("triangle.csh");
+	ui_shader = (Shader*)assets.load("ui.csh");
 	texture = (Texture*)assets.load("22.tex");
 	texture2 = (Texture*)assets.load("kita.tex");
 	cbuf = dev->create_buffer(
@@ -103,6 +111,8 @@ int main() {
 		per_frame_memory_size
 	);
 	clamped_linear = create_clamped_linear(dev);
+	ui = UI::create(dev, &ui_arena, ui_shader->id);
+	ui->create_label("Hello, world", 10, 15);
 	assert(per_frame != 0);
 	uint8_t r = 0;
 	vbo = upload_verts(dev);
@@ -113,6 +123,8 @@ int main() {
 		app->begin();
 		dev->begin_frame();
 
+		ui->update(&frame_arena);
+
 		{
 			void* mem;
 			mem = dev->map_buffer(cbuf, 0, sizeof(Config_Buffer));
@@ -154,11 +166,14 @@ int main() {
 
 		dev->get_ctx().submit(draw, pip, pass);
 
+		ui->render(&frame_arena, dev->get_backbuffer());
+
 		r += 10;
 		frame++;
 		dev->present();
 		app->end();
 	}
+	ui->destroy();
 	assets.destroy();
 	dev->destroy_sampler(clamped_linear);
 	dev->destroy_buffer(vbo);
diff --git a/intermediate/ui.glsl b/intermediate/ui.glsl
new file mode 100644
index 0000000..e40d3d5
--- /dev/null
+++ b/intermediate/ui.glsl
@@ -0,0 +1,56 @@
+#ifdef DESC
+[program]
+type: graphics
+vertex: main
+fragment: main
+
+[binding]
+name: verts
+rate: vertex
+[attribute]
+name: position
+type: vec2
+[attribute]
+name: uv
+type: vec2
+[attribute]
+name: colour
+type: vec4
+
+[interpolator]
+name: colour
+type: vec4
+[interpolator]
+name: uv
+type: vec2
+
+[texture]
+name: atlas
+stage: fragment
+dimension: 2
+
+[target]
+name: colour
+type: vec4
+
+#endif
+
+#ifdef VERTEX_SHADER
+
+void main() {
+	interpolator.colour = colour;
+	interpolator.uv = uv;
+	gl_Position = vec4(position, 0.0, 1.0);
+}
+
+#endif
+
+#ifdef FRAGMENT_SHADER
+
+void main() {
+	vec4 c = texture(atlas, interpolator.uv).r.xxxx;
+	c *= interpolator.colour;
+	colour = c;
+}
+
+#endif
diff --git a/todo.txt b/todo.txt
index d17a86d..33dbce5 100644
--- a/todo.txt
+++ b/todo.txt
@@ -6,7 +6,7 @@ todo list
  - [x] texture conversion + compression, etc
  - [x] texture the triangle
  - [x] refactor pipelines and vertex formats to be more flexible
- - [ ] simple text rendering
+ - [x] simple text rendering
  - [ ] 3D maths library
  - [ ] model conversion
  - [ ] render a model
diff --git a/ui.cpp b/ui.cpp
new file mode 100644
index 0000000..3f773f5
--- /dev/null
+++ b/ui.cpp
@@ -0,0 +1,275 @@
+#include "ui.hpp"
+
+extern "C" {
+#include "memory.h"
+#include "plat.h"
+#include "str.h"
+}
+
+#include <string.h>
+
+#define mesh_size (1024 * 8)
+
+static int font_w = 960;
+static unsigned font_data[] = {
+	0x00000000, 0x00003000, 0x00000000, 0x00000000, 0x00000000,
+	0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000,
+	0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000,
+	0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000,
+	0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000,
+	0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000,
+	0x0cc0c000, 0x8000301b, 0x60601803, 0x00000000, 0x20000000,
+	0x0780c078, 0x83f0e01e, 0xe0783f07, 0x60000001, 0x1e018000,
+	0x07e0c078, 0xe3f87e1f, 0xe0cc1e0f, 0x1e638f01, 0x1f0c6318,
+	0x07e1f07e, 0xc330fc1e, 0x30cc318c, 0x021e0fc3, 0x000101e0,
+	0x00e00000, 0x0000e000, 0xc00e0007, 0x3c038c00, 0x00000000,
+	0x00000000, 0x00001000, 0x00000000, 0x30380000, 0x0000c070,
+	0x0cc1e000, 0xc630f81b, 0xc0301806, 0x00000cc0, 0x30000000,
+	0x0cc0f0cc, 0xc030f033, 0x30cc330c, 0x30000003, 0x33030000,
+	0x8cc1e0cc, 0xc230cc33, 0xc0cc3308, 0x0c630600, 0x318ce3b8,
+	0x0cc318cc, 0xc330b433, 0x30cc318c, 0x06060cc3, 0x00038180,
+	0x00c00018, 0x8000c000, 0x000c000d, 0x30030000, 0x00000000,
+	0x00000000, 0x00001800, 0x00000000, 0x300c0000, 0x0409e0c0,
+	0x8481e000, 0xc3300c3f, 0x80180c06, 0x000c0781, 0x18000000,
+	0x0c00c0ec, 0xc1f0d830, 0x30cc1800, 0x180c0303, 0x30060000,
+	0x8cc330ec, 0xc0318c01, 0xc0cc3180, 0x0c330600, 0x318de3f8,
+	0x0cc318cc, 0xc3303003, 0x3078318c, 0x0c060643, 0x0006c180,
+	0x07c0f018, 0x81e0f81e, 0xf06c3701, 0x30330f00, 0x1e07c1f8,
+	0x0ee37076, 0xc330fc3e, 0x30c6318c, 0x300c0fc3, 0x0e0f20c0,
+	0x0001e000, 0x8180781b, 0x80180013, 0x000c1fe1, 0x0c000000,
+	0x0600c0dc, 0xc300cc1c, 0xe0780c07, 0x0c0c0303, 0x180c03f0,
+	0x87c330ec, 0xc1f18c01, 0xc0fc0187, 0x0c1f0600, 0x318fe358,
+	0x07c3187c, 0xc330300e, 0xe030358c, 0x18060301, 0x000c6180,
+	0x0cc18030, 0xc330cc33, 0xc0dc1987, 0x301b0c00, 0x330cc358,
+	0x0dc198cc, 0xc3301803, 0x306c358c, 0x00060643, 0x1b060180,
+	0x0000c000, 0xc0c0c01b, 0x8018001e, 0x003f0781, 0x060003f0,
+	0x0300c0cc, 0xc301fc30, 0x00cc0c0c, 0x0c000003, 0x0c0c0000,
+	0x8cc3f00c, 0xc0318c01, 0xc0cc3980, 0x0c330660, 0x318f6318,
+	0x06c3980c, 0xc3303018, 0xc078358c, 0x30060180, 0x00000180,
+	0x0cc1f000, 0x83f0cc03, 0xc0cc1981, 0x301f0c00, 0x330cc358,
+	0x00c198cc, 0xc330181e, 0x3038358c, 0x300c0303, 0x318000c0,
+	0x80000000, 0xc6607c3f, 0xc030000c, 0x300c0cc0, 0x03030000,
+	0x0180c0cc, 0xc330c033, 0x30cc0c0c, 0x180c0303, 0x000603f0,
+	0x8cc3308c, 0xc230cc33, 0xc0cc3300, 0x8c630660, 0x318e6318,
+	0x0cc1f00c, 0x83303033, 0xc0cc1f07, 0x600609c0, 0x00000180,
+	0x0cc19800, 0x8030cc33, 0xc0cc1f01, 0x30330cc0, 0x330cc358,
+	0x00c198cc, 0x8330d830, 0xe06c1f07, 0x300c0981, 0x318000c0,
+	0x0000c000, 0x8630301b, 0x6060001b, 0x300c0000, 0x01830000,
+	0x0fc3f078, 0x81e0c01e, 0xe0780c07, 0x300c0301, 0x0c030000,
+	0x07e33078, 0xe3f87e1f, 0xe0cc3e01, 0xfe6383c1, 0x1f0c6318,
+	0x0ce3c01e, 0x01e0781e, 0xe0cc1b03, 0xc01e0fc1, 0x000001e0,
+	0x07e3f000, 0xc1e0f81e, 0xf0ce1803, 0xfc338783, 0x1e0cc318,
+	0x01e1f07c, 0x06e0701f, 0x80c61b03, 0x30380fc1, 0x3f800070,
+	0x0000c000, 0x0000301b, 0x00000000, 0x18000000, 0x00800000,
+	0x00000000, 0x00000000, 0x00000000, 0x60060000, 0x00018000,
+	0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000,
+	0x00000000, 0x00000000, 0x00000000, 0x80000000, 0x7f800000,
+	0x00000000, 0x00000000, 0x00000f00, 0x00000000, 0x00000000,
+	0x0001800c, 0x00000000, 0xf0000000, 0x00000000, 0x00000000,
+	0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000,
+	0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000,
+	0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000,
+	0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000,
+	0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000,
+	0x0003c01e, 0x00000000, 0x00000000, 0x00000000, 0x00000000
+};
+
+static Texture_Id create_atlas(Device* d, Arena* a) {
+	int x, y;
+	int size = 10 * font_w;
+	uint8_t* pixels = (uint8_t*)arena_alloc(a, size);
+	void* bufmem;
+	Buffer_Id buf;
+	Texture_Id tex;
+	for (y = 0; y < 10; y++) {
+		for (x = 0; x < font_w; x++) {
+			int si = x + y * font_w;
+			unsigned bits = font_data[si >> 5];
+			int bit = bits & 1 << (si & 0x1f);
+			pixels[si] = bit? 0xff: 0x00;
+		}
+	}
+	buf = d->create_buffer(
+		size,
+		Buffer_Flags::copy_src |
+		Buffer_Flags::cpu_readwrite
+	);
+	bufmem = d->map_buffer(buf, 0, size);
+	memcpy(bufmem, pixels, size);
+	d->unmap_buffer(buf);
+	tex = d->create_texture(
+		texture_format_r8i,
+		font_w,
+		10,
+		buf
+	);
+	d->destroy_buffer(buf);
+	clear_arena(a);
+	return tex;
+}
+
+static Sampler_Id create_clamped_point(Device* dev) {
+	Sampler_State s{};
+	s.min = Filter_Mode::point;
+	s.mag = Filter_Mode::point;
+	s.address_u = Address_Mode::clamp;
+	s.address_v = Address_Mode::clamp;
+	return dev->create_sampler(s);
+}
+
+UI* UI::create(Device* dev, Arena* a, Shader_Id sh) {
+	Texture_Id atlas = create_atlas(dev, a);
+	UI* u = (UI*)arena_alloc(a, sizeof *u);
+	u->init(dev, a, atlas, sh);
+	return u;
+}
+
+int UI::text_width(const char* t) {
+	int w;
+	for (w = 0; *t; t++) w += 10;
+	return w;
+}
+
+int UI::text_height(const char* t) {
+	(void)t;
+	return 10;
+}
+
+void UI::init(Device* dev, Arena* a, Texture_Id at, Shader_Id sh) {
+	Shader* sp;
+	arena = a;
+	device = dev;
+	tree = 0;
+	atlas = at;
+	shader = sh;
+	mesh = device->create_buffer(
+		mesh_size,
+		Buffer_Flags::vertex_buffer |
+		Buffer_Flags::cpu_readwrite
+	);
+	sp = &dev->get_shader(sh);
+	vertex_format = sp->vf;
+	shader_info.vert_binding = sp->binding_index("verts");
+	shader_info.atlas_binding = sp->descriptor_binding("atlas");
+	sampler = create_clamped_point(device);
+}
+
+void UI::destroy() {
+	device->destroy_texture(atlas);
+	device->destroy_buffer(mesh);
+	device->destroy_sampler(sampler);
+}
+
+int UI::Element::size(Type t) {
+	switch (t) {
+		case Type::label:
+			return sizeof(Label);
+	}
+	assert(0);
+	return 0;
+}
+
+UI::Element* UI::create_element(Element::Type t) {
+	Element* e = (Element*)arena_alloc(arena, Element::size(t));
+	e->type = t;
+	e->next = 0;
+	if (tree)
+		tree->next = e;
+	else
+		tree = e;
+	return e;
+}
+
+UI::Label* UI::create_label(const char* t, int x, int y) {
+	Label* l = (Label*)create_element(Element::Type::label);
+	l->text = dup_string(arena, t);
+	l->len = string_len(t);
+	l->x = x;
+	l->y = y;
+	l->w = text_width(t);
+	l->h = text_height(t);
+	return l;
+}
+
+void UI::update(Arena* s) {
+
+}
+
+int UI::render_label(const Label* l, int off) {
+	int vc = 6 * l->len, i;
+	int x = l->x;
+	int y = l->y;
+	const char* c;
+	float o = 10.0f * ndc[0];
+	Vertex* verts = (Vertex*)device->map_buffer(
+		mesh,
+		off * sizeof(Vertex),
+		vc * sizeof(Vertex)
+	);
+	for (i = 0, c = l->text; i < vc; i += 6, c++) {
+		float uo = (float)((*c - ' ') * 10) / (float)font_w;
+		float w = 10.0f / (float)font_w;
+		float uv[2] = {
+			uo, uo + w
+		};
+		verts[i] = Vertex {
+			(float)x * ndc[0], (float)y * ndc[1], uv[0], 0.0f, 1.0f, 1.0f, 1.0f, 1.0f
+		};
+		verts[i + 1] = Vertex {
+			(float)x * ndc[0], (float)y * ndc[1] + o, uv[0], 1.0f, 1.0f, 1.0f, 1.0f, 1.0f
+		};
+		verts[i + 2] = Vertex {
+			(float)x * ndc[0] + o, (float)y * ndc[1] + o, uv[1], 1.0f, 1.0f, 1.0f, 1.0f, 1.0f
+		};
+		verts[i + 3] = Vertex {
+			(float)x * ndc[0], (float)y * ndc[1], uv[0], 0.0f, 1.0f, 1.0f, 1.0f, 1.0f
+		};
+		verts[i + 4] = Vertex {
+			(float)x * ndc[0] + o, (float)y * ndc[1], uv[1], 0.0f, 1.0f, 1.0f, 1.0f, 1.0f
+		};
+		verts[i + 5] = Vertex {
+			(float)x * ndc[0] + o, (float)y * ndc[1] + o, uv[1], 1.0f, 1.0f, 1.0f, 1.0f, 1.0f
+		};
+		x += 10;
+	}
+	device->unmap_buffer(mesh);
+	return vc;
+}
+
+void UI::render(Arena* s, Texture_Id target) {
+	Element* e = tree;
+	int vc = 0;
+	Texture& t = device->get_texture(target);
+	ndc[0] = 4.0f / (float)t.w;
+	ndc[1] = 4.0f / (float)t.h;
+	for (; e; e = e->next) {
+		switch (e->type) {
+			case Element::Type::label:
+				vc += render_label((Label*)e, vc);
+				break;
+		}
+	}
+
+	Pipeline_Builder pb(s);
+	pb.begin_rp();
+	pb.rp_target(device->get_backbuffer(), Clear_Mode::restore);
+	Render_Pass& pass = pb.build_rp();
+
+	pb.begin(device);
+	pb.shader(shader);
+	pb.vertex_format(vertex_format);
+	pb.texture(shader_info.atlas_binding, atlas, sampler);
+	Pipeline& pip = pb.build();
+
+	Vertex_Buffer_Binding binding[] = {{
+		.id = mesh,
+		.offset = 0,
+		.target = shader_info.vert_binding
+	}, {}};
+
+	Draw draw{};
+	draw.verts = binding;
+	draw.vertex_count = vc;
+	draw.instance_count = 1;
+	device->get_ctx().submit(draw, pip, pass);
+}
diff --git a/ui.hpp b/ui.hpp
new file mode 100644
index 0000000..a181afe
--- /dev/null
+++ b/ui.hpp
@@ -0,0 +1,60 @@
+#ifndef ui_hpp
+#define ui_hpp
+
+#include "video.hpp"
+
+struct Arena;
+struct UI {
+	struct Rect {
+		int x, y, w, h;
+	};
+
+	struct Element : Rect {
+		enum class Type {
+			label
+		} type;
+		Element* next;
+		static int size(Type t);
+	};
+
+	struct Label : Element {
+		char* text;
+		int len;
+		int x, y;
+	};
+
+	struct Vertex {
+		float x, y, u, v, r, g, b, a;
+	};
+
+	Arena* arena;
+	Device* device;
+	Element* tree;
+	Texture_Id atlas;
+	Shader_Id shader;
+	Vertex_Format_Id vertex_format;
+	Buffer_Id mesh;
+	Sampler_Id sampler;
+	struct {
+		int vert_binding;
+		int atlas_binding;
+	} shader_info;
+	float ndc[2];
+
+	static int text_width(const char* t);
+	static int text_height(const char* t);
+
+	static UI* create(Device* dev, Arena* a, Shader_Id sh);
+
+	Element* create_element(Element::Type t);
+	Label* create_label(const char* t, int x, int y);
+
+	void init(Device* dev, Arena* a, Texture_Id atlas, Shader_Id sh);
+	void destroy();
+	void update(Arena* s);
+	void render(Arena* s, Texture_Id target);
+
+	int render_label(const Label* l, int off);
+};
+
+#endif
-- 
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